Pressure Extrusion

Pressure Extrusion 

Pressure Extrusion is a cable and polymer manufacturing process where the insulating or sheathing material is applied under pressure onto a conductor.

In this method, the molten material (such as PVC or XLPE) is forced through an extruder and then through a crosshead die, where it is tightly pressed around the moving conductor.

Key idea

The material is applied under high pressure, so it fully surrounds the conductor and bonds closely to it.

Main features

• ✔ Strong adhesion between conductor and insulation
• ✔ No air gaps between layers
• ✔ Produces smooth, uniform coating
• ✔ High mechanical strength of finished cable

Common uses

• Power cables (PVC, XLPE insulation)
• Industrial wiring
• High-performance electrical cables

Simple explanation

Think of it like squeezing soft melted plastic very tightly around a wire, so it sticks perfectly without leaving any space.

    Comparison table of Tube Extrusion vs                 Pressure Extrusion:

Feature	Tube Extrusion	Pressure Extrusion
Basic idea	Material forms a loose tube around the conductor	Molten material is tightly pressed around the conductor
Contact with conductor	No direct pressure contact	Strong pressure contact
Adhesion (bonding)	Low to moderate adhesion	Very strong adhesion
Air gaps	May have small air gaps	No air gaps
Application method	Tube is formed first, conductor passes inside	Material is forced directly onto conductor
Insulation quality	Moderate	High quality, uniform insulation
Common use	Communication cables, light-duty cables	Power cables (PVC, XLPE), industrial cables
Strength	Lower mechanical strength	Higher mechanical strength
Cost & process	Simpler and faster	More controlled, slightly complex

Easy memory trick:

• Tube extrusion = “loose sleeve”
• Pressure extrusion = “tight squeeze”